Selected Publications
A comparative analysis of the efficiency, timing, and permanence of CO2 removal pathways.
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Carbon dioxide removal (CDR) is essential to deliver the climate objectives of the Paris Agreement. Whilst several CDR pathways have been identified, they vary significantly in terms of CO2 removal efficiency, elapsed time between their deployment and effective CO2 removal, and CO2 removal permanence. All these criteria are critical for the commercial-scale deployment of CDR. In this study, we evaluate a set of archetypal CDR pathways—including afforestation/reforestation (AR), bioenergy with carbon capture and storage (BECCS), biochar, direct air capture of CO2 with storage (DACCS) and enhanced weathering (EW)—through this lens. We present a series of thought experiments, considering different climates and forest types for AR, land types, e.g. impacting biomass yield and (direct and indirect) land use change, and biomass types for BECCS and biochar, capture processes for DACCS, and rock types for EW. Results show that AR can be highly efficient in delivering CDR, up to 95–99% under optimal conditions. However, regional bio-geophysical factors, such as the near-term relatively slow and limited forest growth in cold climates, or the long-term exposure to natural disturbances, e.g. wildfires in warm and dry climates, substantially reduces the overall CO2 removal efficiency of AR. Conversely, BECCS delivers immediate and permanent CDR, but its CO2 removal efficiency can be significantly impacted by any initial carbon debt associated with (direct and indirect) land use change, and thereby significantly delayed. Biochar achieves low CDR efficiency, in the range of 20–39% when it is first integrated with the soil, and that regardless of the biomass feedstock considered. Moreover, its CO2 removal efficiency can decrease to −3 to 5% with time, owing to the decay of biochar. Finally, as for BECCS, DACCS and EW deliver permanent CO2 removal, but their CO2 removal efficiencies are substantially characterized by the energy system within which they are deployed, in the range of −5 to 90% and 17–92%, respectively, if currently deployed. However, the CDR efficiency of EW can increase to 51–92% with time, owing to the carbonation rate of EW.
CO2 mitigation or removal: The optimal uses of biomass in energy system decarbonization.
Owing to its versatility, biomass can be used for a range of CO2 mitigation and removal options. The recent adoption of end-of-century temperature targets at the global scale, along with mid-century economy-wide net zero emission targets in Europe, has boosted demand forecasts for this valuable resource. Given the limited nature of sustainable biomass supply, it is important to understand most efficient uses of biomass, both in terms of avoided CO2 emissions (i.e., substituted energy and economic services) and CO2 removal.
This paper quantifies the mitigation and removal potential of key bio-based CO2 removal pathways for the transport, power, construction, and iron and steel sectors in Europe. By combining the carbon balance of these pathways with their economics, the optimal use of biomass in terms of CO2 avoidance and removal costs is quantified, and how these evolve with the decarbonization of the European energy system is discussed.
Patrizio P., Fajardy M., Bui M., Mac Dowell N. | 2021 | iScience, 7:24
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Socially equitable energy systems transition.
To date, the scientific and policy debates around energy systems transition have mainly focused on the cost performance of energy technologies. However, this ‘one-size-fits-all’ approach ignores the current state of a country’s energy economy and industrial strengths, which could lead to social inequalities and hinder the implementation of national decarbonization strategies.
This paper proposes a modelling framework to identify socially valuable energy systems transition pathways. The results show that in countries such as Poland transitioning to net zero will inevitably bring adverse socio-economic implications. Conversely, countries like Spain seem well-placed to benefit from the transition, owning to the presence of strong industrial expertise in low-carbon technology manufacturing. In all cases, maximizing social value and protecting national strategic assets is key to delivering a technically feasible, financially viable, and socially inclusive transition.
Patrizio P., Pratama Y., Mac Dowell N. | 2020 | Joule, 8: 1700-1713
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Unlocking the potential of BECCS with indigenous sources of biomass at a national scale.
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Bioenergy with carbon capture and storage (BECCS) could play a large role in meeting the 1.5C argets, but faces well-documented controversy in terms of land-use concerns, competition with food production, and cost. This study presents a bottom-up assessment of the scale at which BECCS plants – biomass pulverised combustion plants (“BECCS” in this study) and bioenergy combustion in combined heat and power plants (BE-CHP-CCS) – can be sustainably deployed to meet national carbon dioxide removal (CDR) targets, considering the use of both primary and secondary (waste-derived) biomass. This paper also presents a comprehensive, harmonised data set, which enables others to build upon this work. Land availability for biomass cultivation, processing, and conversion is quantified based on a land-use analysis, avoiding all competition with land used for food production, human habitation, and other protected areas. We find that secondary biomass sources provide a valuable supplement to primary biomass, augmenting indigenous biomass supplies. In initial phases of deployment, we observe that infrastructure is initially clustered near cities, and other sources of low cost, secondary biomass, but as CDR targets are increased and indigenous secondary biomass supplies are exhausted, infrastructure begins to move closer to potential biomass planting areas with higher yield. In minimising the cost of CDR on a cost per tonne CO2 removed basis, we find that the availability of secondary biomass, land availability, and yield are key factors that drive the cost of CDR. Importantly biomass conversion efficiency of a BECCS plant has an inverse effect on CDR costs, with less efficient plants resulting in lower costs compared to their more efficient counterparts. By consuming secondary biomass in BECCS and BE-CHP-CCS plants, the UK is able to be self-sufficient in biomass supply by utilising available indigenous biomass to remove up to 50 MtCO2 /yr, though for cost reasons, it may be preferable to import some biomass.oes here
Reducing emissions of the fast-growing Vietnamese coal sector: The chances offered by biomass co-firing
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Vietnam's Power Development Plan 7A authorized many new coal power plants projects, implying an increase of greenhouse gases emissions from 90 MtCO2eq/year today to 360 MtCO2eq/year in 2030. How could co-firing technology –that is the partial substitution of coal by biomass– contributes to mitigate that problem? In this study, we assess the costs and potentials of co-firing rice residues in present and planned coal power plants in Vietnam using a spatially explicit optimization model: BeWhere, adapted as recursive annual dynamic. We found that, the cost of CO2 emissions is the key parameter determining at what level the technology is used. A cost of CO2 emissions of 8 $/tCO2 mobilizes the maximum technical potential of the rice straw and husk domestic resource, with an annual emission reduction of 28 MtCO2eq/year by 2030. At this level, biomass co-firing contributes to an 8% emission reduction in the coal power sector with the abatement cost of 137 Million USD.
Truong AH, Patrizio P, Leduc S, Kraxner F, Ha-Duong M | 2019 | Journal of Cleaner Production, Vol: 215, Pages: 1301-1311 | ISSN: 0959-6526
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Achieving carbon-neutral iron and steelmaking in Europe through the deployment of bioenergy with carbon capture and storage.
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The 30 integrated steel plants operating in the European Union (EU) are among the largest single-point CO2 emitters in the region. The deployment of bioenergy with carbon capture and storage (bio-CCS) could significantly reduce their emission intensities. In detail, the results demonstrate that CO2 emission reduction targets of up to 20% can be met entirely by biomass deployment. A slow CCS technology introduction on top of biomass deployment is expected, as the requirement for emission reduction increases further. Bio-CCS could then be a key technology, particularly in terms of meeting targets above 50%, with CO2 avoidance costs ranging between €60 and €100 tCO2−1 at full-scale deployment. The future of bio-CCS and its utilisation on a larger scale would therefore only be viable if such CO2 avoidance costs were to become economically appealing. Small and medium plants in particular, would economically benefit from sharing CO2 pipeline networks. CO2 transport, however, makes a relatively small contribution to the total CO2 avoidance cost. In the future, the role of bio-CCS in the European iron and steelmaking industry will also be influenced by non-economic conditions, such as regulations, public acceptance, realistic CO2 storage capacity, and the progress of other mitigation technologies.
Impact of bus electrification on carbon emissions: The case of Stockholm.
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This paper focuses on the potential impact of various options for decarbonization of public bus transport in Stockholm, with particular attention to electrification. An optimization model is used to locate electric bus chargers and to estimate the associated carbon emissions, using a life cycle perspective and various implementation scenarios. Emissions associated with fuels and batteries of electric powertrains are considered to be the two main factors affecting carbon emissions. The results show that, although higher battery capacities could help electrify more routes of the city’s bus network, this does not necessarily lead to a reduction of the total emissions. The results show the lowest life cycle emissions occurring when electric buses use batteries with a capacity of 120 kWh. The fuel choices significantly influence the environmental impact of a bus network. For example, the use of electricity is a better choice than first generation biofuels from a carbon emission perspective. However, the use of second-generation biofuels, such as Hydrotreated Vegetable Oil (HVO), can directly compete with the Nordic electricity mix. Among all fuel options, certified renewable electricity has the lowest impact. The analysis also shows that electrification could be beneficial for reduction of local pollutants in the Stockholm inner city; however, the local emissions of public transport are much lower than emissions from private transport.
Xylia M, Leduc S, Laurent A-B, Patrizio P, Meer YVD, Kraxner F, Silveira S | 2019 | Journal of Cleaner Production, Vol: 209, Pages: 74-87 | ISSN: 0959-6526
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Reducing US coal emissions can boost employment.
Historically, the knock-on effects of environmental regulation on employment have played a central role in the political debate in the US. In this work, we conducted a techno-economic study of the US coal sector that aims to capture the socioeconomic effects of technology transition initiated by climate policies, i.e. achieving 2050 emission reductions in the US coal sectors that are consistent with the 2C target. Results show that the cost-optimal strategy for meeting these targets is through the early deployment of BECCS and by replacing 50% of aging coal plants with natural gas plants. This strategy also helps to address the socio-economic concern by saving jobs otherwise displaced by the premature coal plants’ retirement and boosting the domestic agricultural and utility sectors.
Patrizio P., Leduc S., Kraxner F., Fuss S., Kindermann G., Mesfun S., Spokas K., Mendoza A., MacDowell N., Wetterlund E., Lundgren J., Dotzauer E., Yowargana P. and Obersteiner M. | 2018 | Joule, 2: 1-16 Pages: 2633-2648 | ISSN:2542-4351
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Identifying effects of land use cover changes and climate change on terrestrial ecosystems and carbon stocks in Mexico.
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Land use cover change (LUCC) has a crucial role in global environmental change, impacting both ecosystem services and biodiversity. Evaluating the trends and possible alternatives of LUCC allows quantification and identification of the hotspots of change. Therefore, this study aims to answer what the most vulnerable ecosystems and the carbon stocks losses to LUCC are under two socioeconomic and climate change (CC) scenarios–Business as Usual (BAU) and Green. The scenarios integrate the Representative Concentration Pathways, and the Shared Socioeconomic Pathways, with a spatially explicit LUCC. Distance to roads and human settlements are the most explicative direct drivers of LUCC. The projections include thirteen categories of natural and anthropogenic covers at a fine resolution for Mexico for the two scenarios. The results show that 83% of deforestation in the country has taken place in tropical dry forests, scrublands, temperate forests, and tropical evergreen forests. Considering the range of distribution of natural vegetation and the impacts of LUCC and CC, tropical dry and evergreen forests, followed by other vegetation and cloud forests are shown to be most vulnerable. By 2011, anthropogenic covers accounted for 26% of the country’s cover, and by 2050, according to the BAU scenario, they could account for 37%. The Green scenario suggests a feasible reduction to 21%. In 1985, Mexico had 2.13 PgC in aboveground biomass, but the LUCC would be responsible for 1–2% of LUCC global emissions, and by 2100, it may account for up to 5%. However, if deforestation were reduced and regeneration increased (Green scenario), carbon stocks would reach 2.14 PgC before 2050. Therefore, identifying which natural covers are the most vulnerable to LUCC and CC, and characterizing the principal drivers of ecosystems loss are crucial to prioritizing areas for implementing actions addressing resources to combat the loss of ecosystems and carbon stocks.Description text goes here
Mendoza-Ponce A, Corona-Núñez R, Kraxner F, Leduc S, Patrizio P | 2018 | Global Environmental Change-Human and Policy Dimensions, Vol:53, Pages: 12-2 | ISSN:0959-3780
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Internalizing the external costs of biogas supply chains in the Italian energy sector.
Whilst biogas has shown to have high CO2 emission mitigation potential especially when used as a substitute for power grid electricity, its production generates local airborne emissions, which are often major concern for local communities. The work uses the external cost methodology to quantify the environmental impact of airborne emissions generated across the lifecycle of biogas energy vectors and their corresponding fossil substitutes. A modelling framework that determines the optimal portfolio of biogas technologies based on different level of emissions reduction priorities, is adopted and applied in a regional case study. It is found that when local externalities are accounted for, fostering the production of bioelectricity and biomethane requires 45%-65% higher premium prices than when only GHG emissions area accounted for. These results, suggest that evaluating the sustainability of biogas technologies based on the life cycle CO2 emissions alone, is not a satisfactory measure to evaluate the sustainability of biogas technologies, and confirm some concerns of local communities for the local impacts of renewable energy plants.
Patrizio P., Leduc S., Chinese D., Kraxner F. | 2017 | Energy, 125: 85-96
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